By the beginning of the 20th century, Montania had lost a huge percentage of its population to the Plague and had become very sparsely populated. By the late-mid 20th century, the country had recovered about 25% of its lost population, with a robust birth rate indicating further growth. Fears are now being voiced that the recent outbreak of a fast spreading new virus in the neighboring country might lead to a pandemic and again cause a severe decline in Montania’s population. However, in a very short time Montania has come up with a vaccine against the virus and is ready to make it commercially available. Therefore, those fears are groundless.
Which of the following, if true, seriously weakens the argument?
A. The vaccine trials were conducted on mice, the only species of mammals that comes nearest to being somewhat biologically similar to humans.
B. Montania shares a robust trade relationship with the infected country and citizens of both are frequent travelers to each other’s countries.
C. There is evidence of the virus’ ability to mutate into different strains extremely quickly.
D. Scientists in Montania have had only moderate success in developing effective vaccines against many viruses.
E. The plague is a bacterial disease and despite the availability of antibiotics, Montania had not been able to stop the Plague from spreading.